U.S. patent application number 10/991216 was filed with the patent office on 2005-06-16 for double clutch transmission.
Invention is credited to Kim, In Chan, Seo, Tae Seok.
Application Number | 20050130795 10/991216 |
Document ID | / |
Family ID | 34651346 |
Filed Date | 2005-06-16 |
United States Patent
Application |
20050130795 |
Kind Code |
A1 |
Kim, In Chan ; et
al. |
June 16, 2005 |
Double clutch transmission
Abstract
Engine torque selectively inputted through first and second
input shafts is received and changed selectively by first and
second output devices respectively having first and second output
shafts. A parking gear is disposed on one of the first and second
output shafts in a transmission case at an axial position thereof
corresponding to one drive gear engaged with one driven gear of
another output shaft
Inventors: |
Kim, In Chan; (Yongin-city,
KR) ; Seo, Tae Seok; (Suwon-city, KR) |
Correspondence
Address: |
MORGAN, LEWIS & BOCKIUS LLP (SF)
2 PALO ALTO SQUARE
PALO ALTO
CA
94306
US
|
Family ID: |
34651346 |
Appl. No.: |
10/991216 |
Filed: |
November 17, 2004 |
Current U.S.
Class: |
475/332 |
Current CPC
Class: |
F16H 63/3416 20130101;
F16H 2200/0052 20130101; Y10T 74/19228 20150115; F16H 2003/0931
20130101; F16H 3/093 20130101; F16H 3/006 20130101; F16H 63/48
20130101 |
Class at
Publication: |
475/332 |
International
Class: |
F16H 037/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 2003 |
KR |
10-2003-0089621 |
Claims
What is claimed is:
1. A double clutch transmission comprising: a main input shaft for
receiving an engine torque; a first input shaft rotating coaxially
with the main input shaft; a second input shaft rotating coaxially
with the main input shaft and about an exterior circumference of
the first input shaft; first and second clutches for selectively
transmitting a torque of the main input shaft to the first and
second input shaft respectively; a drive gear unit including a
plurality of drive gears disposed respectively on the first and
second input shafts; a first output device including a first output
shaft disposed parallel to and apart from the main input shaft by a
predetermined distance and having a plurality of driven gears and a
first output gear thereon, such that torques of drive gears on the
first and second input shafts are selectively changed and output; a
second output device including a second output shaft disposed
parallel to and apart from the main input shaft by a predetermined
distance and having a plurality of driven gears, a second output
gear, and a reverse driven gear thereon, such that torques of drive
gears on the first and second input shafts are selectively changed
and output; a differential gear commonly connected to the first
output gear and the second output gear; and a parking gear disposed
on one output shaft of the first and second output shafts in a
transmission case at an axial position thereof corresponding to one
drive gear engaged with one driven gear of another output
shaft.
2. The double clutch transmission of claim 1, wherein the drive
gear unit comprises: first and third drive gears formed on one
input shaft among the first and second input shafts; and second,
fourth, and sixth drive gears formed on another input shaft among
the first and second input shafts.
3. The double clutch transmission of claim 2, wherein the first
output device comprises: the first output shaft; first, second, and
third driven gears disposed on the first output shaft and
respectively engaged with the first, second, and third drive gears;
a first synchronizing device for selectively transmitting torques
of the first and third driven gears to the first output shaft; a
second synchronizing device for selectively transmitting a torque
of the second driven gear to the first output shaft; the first
output gear disposed on the first output shaft and engaged with the
differential gear; and the parking gear disposed on the first
output shaft at an axial position thereof corresponding to one
drive gear on the second input shaft between the second driven gear
and the first output gear, the parking gear being disengaged from
the one drive gear, such that torques of the first, second, and
third drive gears on the first and second input shafts are
selectively changed and output.
4. The double clutch transmission of claim 3, wherein the one drive
gear on the second input shaft is the sixth drive gear.
5. The double clutch transmission of claim 3, wherein the second
output device comprises: the second output shaft; fourth, fifth,
and sixth driven gears disposed on the second output shaft and
respectively engaged with the fourth, third, and sixth drive gears;
a first mediating gear engaged with the first drive gear; a second
mediating gear connected to the first mediating gear by an idle
shaft; the reverse driven gear engaged with the second mediating
gear and disposed on the second output shaft between the first
mediating gear and the fourth driven gear such that at least some
gear teeth of the reverse driven gear are close to an exterior
circumference of an input shaft between the first and fourth drive
gears; a third synchronizing device for selectively transmitting
torques of the fifth driven gear and the reverse driven gear to the
second output shaft; a fourth synchronizing device for selectively
transmitting torques of the fourth driven gear and the sixth driven
gear to the second output shaft; and the second output gear
disposed on the second output shaft and engaged with the
differential gear, such that torques of the first, third, fourth,
and sixth drive gears on the first and second input shafts are
selectively changed and output.
6. The double clutch transmission of claim 2, wherein the first,
second, third, fourth, and sixth drive gears are disposed in a
sequence of the third drive gear, the first drive gear, the fourth
drive gear, the second drive gear, and the sixth drive gear.
7. The double clutch transmission of claim 2, wherein: the first
and third drive gears are formed on the first input shaft; and the
second, fourth, and sixth drive gears are formed on the second
input shaft.
8. The double clutch transmission of claim 2, wherein the first
output device comprises: the first output shaft; first, second,
third, and fourth driven gears disposed on the first output shaft
and respectively engaged with the first, second, third, and fourth
drive gears; a first synchronizing device for selectively
transmitting torques of the first and third driven gears to the
first output shaft; a second synchronizing device for selectively
transmitting torques of the second and fourth driven gears to the
first output shaft; and the first output gear disposed on the first
output shaft and engaged with the differential gear, such that
torques of the first, second, third, and fourth drive gears on the
first and second input shafts are selectively changed and
output.
9. The double clutch transmission of claim 8, wherein the second
output device comprises: the second output shaft; fifth and sixth
driven gears disposed on the second output shaft and respectively
engaged with the third and sixth drive gears; a first mediating
gear engaged with the first drive gear; a second mediating gear
connected to the first mediating gear by an idle shaft; the reverse
driven gear engaged with the second mediating gear and disposed on
the second output shaft between the sixth driven gear and the
second output gear such that at least some gear teeth of the
reverse driven gear are close to an exterior circumference of the
second input shaft between the second and fourth drive gears; a
third synchronizing device for selectively transmitting a torque of
the fifth driven gear and the sixth driven gear to the second
output shaft; a fourth synchronizing device for selectively
transmitting torques of the sixth driven gear and the reverse
driven gear to the second output shaft; the second output gear
disposed on the second output shaft and engaged with the
differential gear; and the parking gear disposed on the second
output shaft at an axial position thereof corresponding to one
drive gear on the second input shaft between the reverse driven
gear and the second output gear, the parking gear being disengaged
from the one drive gear, such that torques of the first, third, and
sixth drive gears on the first and second input shafts are
selectively changed and output.
10. The double clutch transmission of claim 9, wherein the one
drive gear on the second input shaft is the fourth drive gear.
11. The double clutch transmission of claim 2, wherein the first,
second, third, fourth, and sixth drive gears are disposed in a
sequence of the third drive gear, the first drive gear, the sixth
drive gear, the second drive gear, and the fourth drive gear.
12. A double clutch transmission comprising: a main input shaft for
receiving an engine torque; a first input shaft rotating coaxially
with the main input shaft; a second input shaft rotating coaxially
with the main input shaft and about an exterior circumference of
the first input shaft; first and second clutches for selectively
transmitting a torque of the main input shaft to the first and
second input shafts respectively; first and third drive gears
formed on one input shaft among the first and second input shafts;
second, fourth, and sixth drive gears formed on another input shaft
among the first and second input shafts; a first output device
including a first output shaft disposed parallel to and apart from
the main input shaft by a predetermined distance and having a
plurality of driven gears and a first output gear thereon, such
that torques of the first, second, and third drive gears on the
first and second input shafts are selectively changed and output; a
second output device including a second output shaft disposed
parallel to and apart from the main input shaft by a predetermined
distance and having a plurality of driven gears, a second output
gear, and a reverse driven gear thereon, such that torques of the
first, third, fourth, and sixth drive gears on the first and second
input shafts are selectively changed and output; a differential
gear commonly connected to the first output gear and the second
output gear; and a parking gear disposed on the first output shaft
in a transmission case at an axial position thereof corresponding
to one drive gear engaged with one driven gear of the second output
shaft.
13. The double clutch transmission of claim 12, wherein: the first
drive gear is used for first and reverse speeds of the
transmission; the second drive gear is used for a second speed of
the transmission; the third drive gear is used for third and fifth
speeds of the transmission; the fourth drive gear is used for
fourth speed of the transmission; and the sixth drive gear is used
for sixth speed of the transmission and also for an engagement with
the parking gear.
14. The double clutch transmission of claim 12, wherein the first
output device comprises: the first output shaft; first, second, and
third driven gears disposed on the first output shaft and
respectively engaged with the first, second, and third drive gears;
a first synchronizing device for selectively transmitting torques
of the first and third driven gears to the first output shaft; a
second synchronizing device for selectively transmitting a torque
of the second driven gear to the first output shaft; the first
output gear disposed on the first output shaft and engaged with the
differential gear; and the parking gear disposed on the first
output shaft at an axial position thereof corresponding to one
drive gear on the second input shaft between the second driven gear
and the first output gear, the parking gear being disengaged from
the one drive gear, such that torques of the first, second, and
third drive gears on the first and second input shafts are
selectively changed and output
15. The double clutch transmission of claim 14, wherein the one
drive gear on the second input shaft is the sixth drive gear.
16. The double clutch transmission of claim 12, wherein the second
output device comprises: the second output shaft; fourth, fifth,
and sixth driven gears disposed on the second output shaft and
respectively engaged with the fourth, third, and sixth drive gears;
a first mediating gear engaged with the first drive gear; a second
mediating gear connected to the first mediating gear by an idle
shaft; the reverse driven gear engaged with the second mediating
gear and disposed on the second output shaft between the first
mediating gear and fourth driven gear such that at least some gear
teeth of the reverse driven gear are close to an exterior
circumference of the second input shaft between the first and
fourth drive gears; a third synchronizing device for selectively
transmitting torques of the fifth driven gear and the reverse
driven gear to the second output shaft; a fourth synchronizing
device for selectively transmitting torques of the fourth driven
gear and the sixth driven gear to the second output shaft; and the
second output gear disposed on the second output shaft and engaged
with the differential gear, such that torques of the first, third,
fourth, and sixth drive gears on the first and second input shafts
are selectively changed and output.
17. The double clutch transmission of claim 12, wherein the first,
second, third, fourth, and sixth drive gears are disposed in a
sequence of the third drive gear, the first drive gear, the fourth
drive gear, the second drive gear, and the sixth drive gear.
18. A double clutch transmission comprising: a main input shaft for
receiving an engine torque; a first input shaft rotating coaxially
with the main input shaft; a second input shaft rotating coaxially
with the main input shaft and about an exterior circumference of
the first input shaft; first and second clutches for selectively
transmitting a torque of the main input shaft to the first and
second input shafts respectively; first and third drive gears
formed on one input shaft among the first and second input shafts;
second, fourth, and sixth drive gears formed on another input shaft
among the first and second input shafts; a first output device
including a first output shaft disposed parallel to and apart from
the main input shaft by a predetermined distance and having a
plurality of driven gears and a first output gear thereon, such
that torques of the first, second, third, and fourth drive gears on
the first and second input shafts are selectively changed and
output; a second output device including a second output shaft
disposed parallel to and apart from the main input shaft by a
predetermined distance and having a plurality of driven gears, a
second output gear, and a reverse driven gear thereon, such that
torques of the first, third, and sixth drive gears on the first and
second input shafts are selectively changed and output; a
differential gear commonly connected to the first output gear and
the second output gear; and a parking gear disposed on the second
output shaft in a transmission case at an axial position thereof
corresponding to one drive gear engaged with one driven gear of the
first output shaft.
19. The double clutch transmission of claim 18, wherein: the first
drive gear is used for first and reverse speeds of the
transmission; the second drive gear is used for a second speed of
the transmission; the third drive gear is used for third and fifth
speeds of the transmission; the fourth drive gear is used for a
fourth speed of the transmission and also for an engagement with
the parking gear; and the sixth drive gear is used for a sixth
speed of the transmission.
20. The double clutch transmission of claim 18, wherein the first
output device comprises: the first output shaft; first, second,
third, and fourth driven gears disposed on the first output shaft
and respectively engaged with the first, second, third, and fourth
drive gears; a first synchronizing device for selectively
transmitting torques of the first and third driven gears to the
first output shaft; a second synchronizing device for selectively
transmitting torques of the second and fourth driven gears to the
first output shaft; and the first output gear disposed on the first
output shaft and engaged with the differential gear, such that
torques of the first, second, third, and fourth drive gears on the
first and second input shafts are selectively changed and
output
21. The double clutch transmission of claim 18, Wherein the second
output device comprises: the second output shaft; fifth and sixth
driven gears disposed on the second output shaft and respectively
engaged with the third and sixth drive gears; a first mediating
gear engaged with the first drive gear; a second mediating gear
connected to the first mediating gear by an idle shaft; the reverse
driven gear engaged with the second mediating gear and disposed on
the second output shaft between the sixth driven gear and the
second output gear such that at lest some gear teeth of the reverse
driven gear are close to an exterior circumference of the second
input shaft between the second and fourth drive gears; a third
synchronizing device for selectively transmitting a torque of the
fifth driven gear and the sixth driven gear to the second output
shaft; a fourth synchronizing device for selectively transmitting
torques of the sixth driven gear and the reverse driven gear to the
second output shaft; the second output gear disposed on the second
output shaft and engaged with the differential gear; and the
parking gear disposed on the second output shaft at an axial
position thereof corresponding to one drive gear on the second
input shaft between the reverse driven gear and the second output
gear, the parking gear being disengaged from the one drive gear,
such that torques of the first, third, and sixth drive gears on the
first and second input shafts are selectively changed and
output.
22. The double clutch transmission of claim 21, wherein the one
drive gear on the second input shaft is the fourth drive gear.
23. The double clutch transmission of claim 18, wherein the first,
second, third, fourth, and sixth drive gears are disposed in a
sequence of the third drive gear, the first drive gear, the sixth
drive gear, the second drive gear, and the fourth drive gear.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of Korean Application No.
10-2003-0089621, file on Dec. 10, 2003, the disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] Generally, the present invention relates to a double clutch
transmission. More particularly, the present invention relates to a
double clutch transmission having, in addition to a reduced length
and enhanced power transmission efficiency, providing a reduced
load on the parking apparatus by disposing a parking gear on an
output shaft in a transmission case.
BACKGROUND OF THE INVENTION
[0003] Generally a double clutch transmission implies a
transmission having two clutch devices therein. A double clutch
transmission generally receives a torque input from an engine
selectively at its two input shafts using two clutches, and it
changes the torque and speed using gears on the two input shafts,
and outputs them.
[0004] Such a double clutch transmission has been devised basically
to compactly provide a multi-speed transmission having more than
five speeds. The two clutches and synchronizing devices included in
a double clutch transmission may be controlled by a controller, and
accordingly, such a double clutch transmission may also realize an
automated shift gear (ASG) that eliminates the necessity of manual
shifting of a driver.
[0005] A clutch included in a double clutch transmission may be
categorized as either a dry- or wet-type based on its operational
scheme. A dry-type clutch utilizes the same principle as a clutch
device conventionally disposed between an engine and a manual
transmission. A wet-type clutch utilizes the same principle as a
clutch device inside an automatic transmission.
[0006] A wet-type clutch generally has a higher torque capacity
than a dry-type clutch. Therefore, for an engine of high output
power, a wet-type clutch is appropriate. In order to stably
transmit high output torque of a high powered engine, the widths of
gears in the transmission should be large. Therefore, a double
clutch transmission designed for a high torque engine may easily
become very lengthy.
[0007] The information disclosed in this Background of the
Invention section is only for enhancement of understanding of the
background of the invention and should not be taken as an
acknowledgement or any form of suggestion that this information
forms the prior art that is already known in this country to a
person of ordinary skill in the art.
SUMMARY OF THE INVENTION
[0008] The present invention provides a double clutch transmission
having non-limiting advantages of, in addition to reduced length
and enhanced power transmission efficiency, a reduced load of a
parking apparatus due to disposing a parking gear on an output
shaft in a transmission case at a position axially corresponding to
a drive gear engaged with a driven gear of another output
shaft.
[0009] The present invention also provides a double clutch
transmission having non-limiting advantages of a simplified linkage
structure for transferring a movement of a shift lever (frequently
called a transmission gear shift lever, and abbreviated as T.G.S
lever) to the manual valve of a valve body by positioning the
parking gear PG on an output shaft close to an inhibitor switch
and/or the manual valve of the transmission case.
[0010] An exemplary double clutch transmission according to an
embodiment of the present invention includes: a main input shaft
for receiving an engine torque; a first input shaft rotating
coaxially with the main input shaft; a second input shaft rotating
coaxially with the main input shaft and along an exterior
circumference of the first input shaft; first and second clutches
for selectively transmitting a torque of the main input shaft to
the first and second input shafts respectively; a drive gear unit
including a plurality of drive gears disposed respectively on the
first and second input shafts; a first output device including a
first output shaft disposed parallel to and apart from the main
input shaft by a predetermined distance and having a plurality of
driven gears and a first output gear thereon, such that torques of
drive gears on the first and second input shafts are selectively
changed and output; a second output device including a second
output shaft disposed parallel to and apart from the main input
shaft by a predetermined distance and having a plurality of driven
gears, a second output gear, and a reverse driven gear thereon,
such that torques of drive gears on the first and second input
shafts are selectively changed and output; a differential gear
commonly connected to the first output gear and the second output
gear; and a parking gear disposed on one output shaft of the first
and second output shafts in a transmission case at an axial
position thereof corresponding to one drive gear engaged with one
driven gear of another output shaft.
[0011] The drive gear unit may include: first and third drive gears
formed on one input shaft among the first and second input shafts;
and second, fourth, and sixth drive gears formed on another input
shaft among the first and second input shafts.
[0012] The first output device may include: the first output shaft;
first, second, and third driven gears disposed on the first output
shaft and respectively engaged with the first, second, and third
drive gears; a first synchronizing device for selectively
transmitting torques of the first and third driven gears to the
first output shaft; a second synchronizing device for selectively
transmitting a torque of the second driven gear to the first output
shaft; the first output gear disposed on the first output shaft and
engaged with the differential gear; and the parking gear disposed
on the first output shaft at an axial position thereof
corresponding to one drive gear on the second input shaft between
the second driven gear and the first output gear, the parking gear
being disengaged from the one drive gear, such that torques of the
first, second, and third drive gears on the first and second input
shafts are selectively changed and output.
[0013] The one drive gear on the second input shaft may be the
sixth drive gear. The second output device may include: the second
output shaft; fourth, fifth, and sixth driven gears disposed on the
second output shaft and respectively engaged with the fourth,
third, and sixth drive gears; a first mediating gear engaged with
the first drive gear; a second mediating gear connected to the
first mediating gear by an idle shaft; the reverse driven gear
engaged with the second mediating gear and disposed on the second
output shaft between the first mediating gear and the fourth driven
gear such that at least some gear teeth of the reverse driven gear
are close to an exterior circumference of an input shaft between
the first and fourth drive gears; a third synchronizing device for
selectively transmitting torques of the fifth driven gear and the
reverse driven gear to the second output shaft; a fourth
synchronizing device for selectively transmitting torques of the
fourth driven gear and the sixth driven gear to the second output
shaft; and the second output gear disposed on the second output
shaft and engaged with the differential gear, such that torques of
the first, third, fourth, and sixth drive gears on the first and
second input shafts are selectively changed and output.
[0014] The first, second, third, fourth, and sixth drive gears may
be disposed in a sequence of the third drive gear, the first drive
gear, the fourth drive gear, the second drive gear, and the sixth
drive gear. The first and third drive gears may be formed on the
first input shaft; and the second, fourth, and sixth drive gears
may be formed on the second input shaft.
[0015] The first output device may include: the first output shaft;
first, second, third, and fourth driven gears disposed on the first
output shaft and respectively engaged with the first, second,
third, and fourth drive gears; a first synchronizing device for
selectively transmitting torques of the first and third driven
gears to the first output shaft; a second synchronizing device for
selectively transmitting torques of the second and fourth driven
gears to the first output shaft; and the first output gear disposed
on the first output shaft and engaged with the differential gear,
such that torques of the first, second, third, and fourth drive
gears on the first and second input shafts are selectively changed
and output.
[0016] The second output device may include: the second output
shaft; fifth and sixth driven gears disposed on the second output
shaft and respectively engaged with the third and sixth drive
gears; a first mediating gear engaged with the first drive gear; a
second mediating gear connected to the first mediating gear by an
idle shaft; the reverse driven gear engaged with the second
mediating gear and disposed on the second output shaft between the
sixth driven gear and the second output gear such that at least
some gear teeth of the reverse driven gear are close to an exterior
circumference of the second input shaft between the second and
fourth drive gears; a third synchronizing device for selectively
transmitting a torque of the fifth driven gear and the sixth driven
gear to the second output shaft; a fourth synchronizing device for
selectively transmitting torques of the sixth driven gear and the
reverse driven gear to the second output shaft; the second output
gear disposed on the second output shaft and engaged with the
differential gear; and the parking gear disposed on the second
output shaft at an axial position thereof corresponding to one
drive gear on the second input shaft between the reverse driven
gear and the second output gear, the parking gear being disengaged
from the one drive gear, such that torques of the first, third, and
sixth drive gears on the first and second input shafts are
selectively changed and output.
[0017] The one drive gear on the second input shaft may be the
fourth drive gear. The first, second, third, fourth, and sixth
drive gears may be disposed in a sequence of the third drive gear,
the first drive gear, the sixth drive gear, the second drive gear,
and the fourth drive gear.
[0018] Another exemplary double clutch transmission according to
the present invention includes: a main input shaft for receiving an
engine torque; a first input shaft rotating coaxially with the main
input shaft; a second input shaft rotating coaxially with the main
input shaft and along an exterior circumference of the first input
shaft; first and second clutches for selectively transmitting a
torque of the main input shaft to the first and second input shafts
respectively; first and third drive gears formed on one input shaft
among the first and second input shafts; second, fourth, and sixth
drive gears formed on another input shaft among the first and
second input shafts; a first output device including a first output
shaft disposed parallel to and apart from the main input shaft by a
predetermined distance and having a plurality of driven gears and a
first output gear thereon, such that torques of the first, second,
and third drive gears on the first and second input shafts are
selectively changed and output; a second output device including a
second output shaft disposed parallel to and apart from the main
input shaft by a predetermined distance and having a plurality of
driven gears, a second output gear, and a reverse driven gear
thereon, such that torques of the first, third, fourth, and sixth
drive gears on the first and second input shafts are selectively
changed and output; a differential gear commonly connected to the
first output gear and the second output gear; and a parking gear
disposed on the first output shaft in a transmission case at an
axial position thereof corresponding to one drive gear engaged with
one driven gear of the second output shaft.
[0019] The first output device may include: the first output shaft;
first, second, and third driven gears disposed on the first output
shaft and respectively engaged with the first, second, and third
drive gears; a first synchronizing device for selectively
transmitting torques of the first and third driven gears to the
first output shaft; a second synchronizing device for selectively
transmitting a torque of the second driven gear to the first output
shaft; the first output gear disposed on the first output shaft and
engaged with the differential gear; and the parking gear disposed
on the first output shaft at an axial position thereof
corresponding to one drive gear on the second input shaft between
the second driven gear and the first output gear, the parking gear
being disengaged from the one drive gear, such that torques of the
first, second, and third drive gears on the first and second input
shafts are selectively changed and output.
[0020] The one drive gear on the second input shaft may be the
sixth drive gear. The second output device may include: the second
output shaft; fourth, fifth, and sixth driven gears disposed on the
second output shaft and respectively engaged with the fourth,
third, and sixth drive gears; a first mediating gear engaged with
the first drive gear; a second mediating gear connected to the
first mediating gear by an idle shaft; the reverse driven gear
engaged with the second mediating gear and disposed on the second
output shaft between the first mediating gear and fourth driven
gear such that at least some gear teeth of the reverse driven gear
are close to an exterior circumference of the second input shaft
between the first and fourth drive gears; a third synchronizing
device for selectively transmitting torques of the fifth driven
gear and the reverse driven gear to the second output shaft; a
fourth synchronizing device for selectively transmitting torques of
the fourth driven gear and the sixth driven gear to the second
output shaft; and the second output gear disposed on the second
output shaft and engaged with the differential gear, such that
torques of the first, third, fourth, and sixth drive gears on the
first and second input shafts are selectively changed and
output.
[0021] The first, second, third, fourth, and sixth drive gears may
be disposed in a sequence of the third drive gear, the first drive
gear, the fourth drive gear, the second drive gear, and the sixth
drive gear.
[0022] Another exemplary double clutch transmission according to
the present invention includes: a main input shaft for receiving an
engine torque; a first input shaft rotating coaxially with the main
input shaft; a second input shaft rotating coaxially with the main
input shaft and along an exterior circumference of the first input
shaft; first and second clutches for selectively transmitting a
torque of the main input shaft to the first and second input shafts
respectively; first and third drive gears formed on one input shaft
among the first and second input shafts; second, fourth, and sixth
drive gears formed on another input shaft among the first and
second input shafts; a first output device including a first output
shaft disposed parallel to and apart from the main input shaft by a
predetermined distance and having a plurality of driven gears and a
first output gear thereon, such that torques of the first, second,
third, and fourth drive gears on the first and second input shafts
are selectively changed and output; a second output device
including a second output shaft disposed parallel to and apart from
the main input shaft by a predetermined distance and having a
plurality of driven gears, a second output gear, and a reverse
driven gear thereon, such that torques of the first, third, and
sixth drive gears on the first and second input shafts are
selectively changed and output; a differential gear commonly
connected to the first output gear and the second output gear; and
a parking gear disposed on the second output shaft in a
transmission case at an axial position thereof corresponding to one
drive gear engaged with one driven gear of the first output
shaft.
[0023] The first output device may include: the first output shaft;
first, second, third, and fourth driven gears disposed on the first
output shaft and respectively engaged with the first, second,
third, and fourth drive gears; a first synchronizing device for
selectively transmitting torques of the first and third driven
gears to the first output shaft; a second synchronizing device for
selectively transmitting torques of the second and fourth driven
gears to the first output shaft; and the first output gear disposed
on the first output shaft and engaged with the differential gear,
such that torques of the first, second, third, and fourth drive
gears on the first and second input shafts are selectively changed
and output.
[0024] The second output device may include: the second output
shaft; fifth and sixth driven gears disposed on the second output
shaft and respectively engaged with the third and sixth drive
gears; a first mediating gear engaged with the first drive gear; a
second mediating gear connected to the first mediating gear by an
idle shaft; the reverse driven gear engaged with the second
mediating gear and disposed on the second output shaft between the
sixth driven gear and the second output gear such that at least
some gear teeth of the reverse driven gear are close to an exterior
circumference of the second input shaft between the second and
fourth drive gears; a third synchronizing device for selectively
transmitting a torque of the fifth driven gear and the sixth driven
gear to the second output shaft; a fourth synchronizing device for
selectively transmitting torques of the sixth driven gear and the
reverse driven gear to the second output shaft; the second output
gear disposed on the second output shaft and engaged with the
differential gear; and the parking gear disposed on the second
output shaft at an axial position thereof corresponding to one
drive gear on the second input shaft between the reverse driven
gear and the second output gear, the parking gear being disengaged
from the one drive gear, such that torques of the first, third, and
sixth drive gears on the first and second input shafts are
selectively changed and output.
[0025] The one drive gear on the second input shaft may be the
fourth drive gear. The first, second, third, fourth, and sixth
drive gears may be disposed in a sequence of the third drive gear,
the first drive gear, the sixth drive gear, the second drive gear,
and the fourth drive gear.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate an embodiment of
the invention, and, together with the description, serve to explain
the principles of the invention:
[0027] FIG. 1 is a schematic diagram of a double clutch
transmission according to a first embodiment of the present
invention;
[0028] FIG. 2 is a drawing for illustrating a spatial relationship
of an idle shaft for a reverse speed, a differential gear, a
parking gear, first and second input shafts, and first and second
output shafts of a double clutch transmission according to a first
embodiment of the present invention;
[0029] FIG. 3 is a schematic diagram of a double clutch
transmission according to a second embodiment of the present
invention;
[0030] FIG. 4 is a drawing for illustrating a spatial relationship
of an idle shaft for a reverse speed, a differential gear, a
parking gear, first and second input shafts, and first and second
output shafts of a double clutch transmission according to a second
embodiment of the present invention;
[0031] FIG. 5 is a schematic diagram of a double clutch
transmission; and
[0032] FIG. 6 is a drawing for illustrating a spatial relationship
of an idle shaft for a reverse speed, a differential gear, a
parking gear, first and second input shafts, and first and second
output shafts of a double clutch transmission shown in FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] In order to address such drawbacks, a double clutch
transmission as shown in FIGS. 5 and 6 has recently been developed.
According to such a double clutch transmission, two input shafts
110 and 120 have a plurality of drive gears G1, G2, G3, G4, and G5
disposed thereon. The drive gears rotate coaxially with and are
connected to a main input shaft 105 via two clutches C1 and C2. A
plurality of driven gears D1, D2, D3, D4, D5, and D6 and a reverse
driven gear R engaged with the drive gears are dividedly disposed
on two output shafts 130 and 140 disposed parallel to the input
shafts 110 and 120. Two output devices OUT1 and OUT2 selectively
change torques of the drive gears and output the changed torques
through a differential gear DIFF.
[0034] However, the space in a transmission case of a double clutch
transmission having two output shafts 130 and 140 is insufficient
for accommodating a parking gear of a parking apparatus in addition
to the drive gears G1, G2, G3, G4, and G5. So, usually, a parking
gear PG is integrally formed with a differential case.
[0035] When the parking gear PG is integrally formed with the
differential case, torque acting on the parking gear PG due to a
weight of a vehicle e.g., on a slope may easily become excessive
since torque acts on the differential case at 3 to 4 times that
which acts on the output shafts 130 and 140. Therefore, a parking
apparatus requires a high torque capacity.
[0036] In addition, the parking gear PG is positioned on the
transmission case far from an inhibitor switch and/or the manual
valve. Therefore, a linkage structure for transferring a movement
of a shift lever (frequently called a transmission gear shift
lever, and abbreviated as T.G.S lever) to the manual valve of a
valve body becomes complex.
[0037] FIG. 6 does not illustrate a connection between the first
mediating gear M1 and the first drive gear G1, or a connection
between the second output shaft 140 and the differential gear DIFF.
This is because the first and second input shafts 110 and 120, the
first and second output shafts 130 and 140, the idle shaft 150, and
the differential gear DIFF are planarly drawn for illustrational
convenience, although they are spatially disposed. Such a spatial
disposition of the first and second input shafts 110 and 120, the
first and second output shafts 130 and 140, the idle shaft 150, and
the differential gear DIFF appears in FIG. 6.
[0038] FIG. 6 is a view of FIG. 5 seen from the right thereof, and
some gears shown in FIG. 5 are intentionally not shown in FIG. 6
for better understanding of the spatial relationship among rotation
axes of rotating element.
[0039] An embodiment of the present invention will hereinafter be
described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of a double clutch transmission
according to a first embodiment of the present invention. As shown
in FIG. 1, a double clutch transmission according to a first
embodiment of the present invention includes a main input shaft
105; first and second input shafts 110 and 120; first and second
clutches C1 and C2; first, second, third, fourth, and sixth drive
gears G1, G2, G3, G4, and G6; first and second output devices OUT1
and OUT2; and a differential gear DIFF. The main input shaft 105
receives a torque of an engine 102. The first input shaft 110
rotates coaxially with the main input shaft 105.
[0040] FIG. 1 illustrates that the main input shaft 105 penetrates
through the first input shaft 110 to be connected to an oil pump
190, and this is only to exemplarily show that a double clutch
transmission of the present invention may be realized as a
wet-type. Therefore, it should not be understood that the scope of
the present invention is limited to as shown in FIG. 1. For
example, for a dry-type double clutch transmission, the first input
shaft 110 may be formed as a rod having no interior space.
[0041] The second input shaft 120 rotates coaxially with the main
input shaft 105 and along an exterior circumference of the first
input shaft 110. The first and second clutches C1 and C2
selectively transmit a torque of the main input shaft 105 to the
first and second input shafts 110 and 120. Therefore, the torque of
the main input shaft 105 is transmitted to the first input shaft
110 under an operation of the first clutch C1, and to the second
input shaft 120 under an operation of the second clutch C2.
[0042] The first and third drive gears G1 and G3 are formed on the
first input shaft 110, and the second, fourth, and sixth drive
gears G2, G4, and G6 are formed on the second input shaft 120. In
further detail, the first and third drive gears G1 and G3 are
disposed on the first input shaft 110 such that an end of the
second input shaft 120 is closer to the first drive gear G1 than to
the third drive gear G3. In addition, the second, fourth, and sixth
drive gears G2, G4, and G6 are disposed on the second input shaft
120 such that the engine 102 is closest to the sixth drive gear G6,
further from the second drive gear G2, and farthest from the fourth
drive gear G4. In other words, regarding disposition of such drive
gears, referring to FIG. 1 related to a first embodiment of the
present invention, the first, second, third, fourth, and sixth
drive gears G1, G2, G3, G4, and G6 are disposed in a sequence of
the third drive gear G3, the first drive gear G1, the fourth drive
gear G4, the second drive gear G2, and the sixth drive gear G6.
[0043] As shown in FIG. 1, a double clutch transmission according
to an embodiment of the present invention further includes a first
output device OUT1 and a second output device OUT2. The first
output device OUT1 selectively changes torques of the first,
second, and third drive gears G1, G2, and G3, and outputs the
changed torques. The second output device OUT2 selectively changes
torques of the first, third, fourth, and sixth drive gears G1, G3,
G4, and G6, and outputs the changed torques.
[0044] As shown in FIG. 1, the first output device OUT1 includes a
first output shaft 130, first, second, and third driven gears D1,
D2, and D3, first and second synchronizing devices S1 and S2, and a
first output gear 135. The first output shaft 130 is disposed
parallel to and apart from the main input shaft 105 by a
predetermined distance. The first, second, and third driven gears
D1, D2, and D3 are disposed on the first output shaft 130, and they
are respectively engaged with the first, second, and third drive
gears G1, G2, and G3.
[0045] The first synchronizing device S1 selectively transmits
torques of the first and third driven gears D1 and D3 to the first
output shaft 130. The second synchronizing device S2 selectively
transmits a torque of the second driven gear D2 to the first output
shaft 130.
[0046] In addition, the first output gear 135 is disposed on the
first output shaft 130 and is engaged with the differential gear
DIFF such that selectively changed torques of the first, second,
and third drive gears G1, G2, and G3 may be output therethrough to
the differential gear DIFF.
[0047] As shown in FIG. 1, the second output device OUT2 includes a
second output shaft 140; fourth, fifth, and sixth driven gears D4,
D5, and D6; first and second mediating gears M1 and M2; a reverse
driven gear R; third and fourth synchronizing devices S3 and S4;
and a second output gear 145. The second output shaft 140 is
disposed parallel to and apart from the main input shaft 105 by a
predetermined distance. The fourth, fifth, and sixth driven gears
D4, D5, and D6 are disposed on the second output shaft 140, and are
respectively engaged with the fourth, third, and sixth drive gears
G4, G3, and G6.
[0048] The first mediating gear M1 is engaged with the first drive
gear G1, and the second mediating gear M2 is connected to the first
mediating gear M1 by an idle shaft 150. The reverse driven gear R
is engaged with the second mediating gear M2 and is disposed on the
second output shaft 140 between the first mediating gear M1 and the
fourth driven gear D4. Gear teeth (more specifically, the outer
surface of some gear teeth) TF of the reverse driven gear R lie
close to an exterior circumference of the first input shaft between
the first and fourth drive gear G1 and G4.
[0049] The third synchronizing device S3 selectively transmits
torques of the fifth driven gear D5 and the reverse driven gear R
to the second output shaft 140. The fourth synchronizing device S4
selectively transmits torques of the fourth driven gear D4 and the
sixth driven gear D6 to the second output shaft 140.
[0050] In addition, the second output gear 145 is disposed on the
second output shaft 140 and engaged with the differential gear DIFF
such that selectively changed torques of the first, third, and
sixth drive gears G1, G3, and G6 may be output therethrough to the
differential gear DIFF.
[0051] In addition, the parking gear PG is disposed on the first
output shaft 130 of the first output device OUT1 between the second
driven gear D2 and the first output gear 135. In this case the
parking gear PG is disposed at an axial position corresponding to
the sixth drive gear G6 of the second input shaft. Therefore,
limited space in a transmission case may be efficiently
utilized.
[0052] In addition, when the parking gear PG is disposed on the
first output shaft 130, torque acting on the parking gear PG due to
a weight of a vehicle e.g., on a slope, is reduced by a reduction
ratio between the differential gear DIFF and the first output gear
135. This implies that a torque capacity of a parking apparatus may
be minimally designed.
[0053] In addition, the parking gear PG may be positioned on the
first output shaft 130 close to an inhibitor switch and/or the
manual valve of the transmission case. Therefore, a linkage
structure for transferring a movement of a shift lever (frequently
called a transmission gear shift lever, and abbreviated as T.G.S
lever) to the manual valve of a valve body may be simplified.
Details of the first, second, third, and fourth synchronizing
devices S1, S2, S3, and S4 may be obviously realized by a person of
ordinary skill in the art referring to synchronizing devices of a
conventional manual transmission.
[0054] An embodiment of the present invention may further include
first, second, third, and fourth actuators (not shown) respectively
for actuating the first, second, third, and fourth synchronizing
devices S1, S2, S3, and S4 to left and right in FIG. 1. In this
case, the first, second, third, and fourth actuators (not shown)
may be driven by a controller (not shown).
[0055] FIG. 1 does not illustrate a connection between the first
mediating gear M1 and the first drive gear G1, or a connection
between the second output shaft 140 and the differential gear DIFF.
This is because the first and second input shafts 110 and 120, the
first and second output shafts 130 and 140, the idle shaft 150, and
the differential gear DIFF are planarly drawn for illustrational
convenience, although they are spatially disposed. Such a spatial
disposition of the first and second input shafts 110 and 120, the
first and second output shafts 130 and 140, the idle shaft 150, the
differential gear DIFF, and the parking gear PG appears in FIG.
2.
[0056] FIG. 2 is a drawing for illustrating a spatial relationship
of an idle shaft 150 for a reverse speed, a differential gear DIFF,
a parking gear PG, first and second input shafts 110 and 120, and
first and second output shafts 130 and 140 of a double clutch
transmission according to a first embodiment of the present
invention. FIG. 2 is a view of FIG. 1 seen from the right thereof,
and some gears shown in FIG. 1 are intentionally not shown in FIG.
2 for better understanding of the spatial relationship among
rotation axes of rotating elements.
[0057] As shown in FIG. 2, the first and second output shafts 130
and 140 are disposed apart from the second input shaft 120. The
idle shaft 150 for a reverse speed is disposed at a position at
which it may form a triangle together with the first input shaft
110 and the second output shaft 140. The first mediating gear M1 on
the idle shaft 150 is engaged with the first drive gear G1 of the
first input shaft 110, and the second mediating gear M2 on the idle
shaft 150 is engaged with the reverse driven gear R of the second
output shaft 140.
[0058] The differential gear DIFF is disposed at a position that it
may form a triangle together with the first and second output
shafts 130 and 140, so that the differential gear DIFF is commonly
engaged with the first and second output gears 135 and 145 of the
first and second output shafts 130 and 140. The parking gear PG on
the first output shaft is not engaged with any gear.
[0059] According to such structural features of a double clutch
transmission, disposition of only five drive gears on input shafts
may enable a total of seven speeds, i.e., six forward speeds and
one reverse speed. Therefore, a length of a forward six-speed
double clutch transmission may be greatly shortened.
[0060] In addition, shortened length of the idle shaft 150 for a
reverse speed contributes to a reduction of rotational inertia of
the transmission in forward speeds, an enhancement of torque
transmission efficiency in the reverse speed, and an increase in
durability of the idle shaft 150 for a reverse speed. In addition,
the parking gear PG is disposed on the first output shaft 130, at
an axial position corresponding to the sixth drive gear G6 of the
second input shaft 120 engaged with the sixth driven gear D6 of the
second output shaft 140.
[0061] Therefore, torque acting on the parking gear PG due to a
weight of a vehicle is reduced by a reduction ratio between the
differential gear DIFF and the first output gear 135.
[0062] In addition, the parking gear PG may be positioned on the
first output shaft 130 closest to an inhibitor switch and/or the
manual valve of the transmission case. Therefore, the linkage
structure for transferring a movement of a shift lever (frequently
called a transmission gear shift lever, and abbreviated as T.G.S
lever) to the manual valve of a valve body may be simplified.
[0063] Referring back to FIG. 1, shifting operations of such a
double clutch transmission according to a first embodiment of the
present invention are hereinafter described in detail. For shifting
to the first speed, the first driven gear D1 and the first output
shaft 130 are synchronously engaged by operating the first
synchronizing device S1 to the right in FIG. 1. Then, the shifting
to the first speed may be terminated by operating the first clutch
C1.
[0064] For shifting to the second speed, firstly, the second driven
gear D2 and the first output shaft 130 are synchronously engaged by
operating the second synchronizing device S2 to the right in FIG. 1
while the first clutch C1 operates and the second clutch C2 is
released. Then, the shifting to the second speed may be terminated
by releasing the first clutch C1 and operating the second clutch
C2.
[0065] For shifting to the third speed, firstly, the third driven
gear D3 and the first output shaft 130 are synchronously engaged by
operating the first synchronizing device S1 to the left in FIG. 1
while the first clutch C1 is released and the second clutch C2
operates. Then, the shifting to the third speed may be terminated
by releasing the second clutch C2 and operating the first clutch
C1.
[0066] For shifting to the fourth speed, firstly, the fourth driven
gear D4 and the second output shaft 140 are synchronously engaged
by operating the fourth synchronizing device S4 to the left in FIG.
1 while the first clutch C1 operates and the second clutch C2 is
released. Then, the shifting to the fourth speed may be terminated
by releasing the first clutch C1 and operating the second clutch
C2.
[0067] For shifting to the fifth speed, firstly, the fifth driven
gear D5 and the second output shaft 140 are synchronously engaged
by operating the third synchronizing device S3 to the left in FIG.
1 while the first clutch C1 is released and the second clutch C2
operates. Then, the shifting to the fifth speed may be terminated
by releasing the second clutch C2 and operating the first clutch
C1.
[0068] For shifting to the sixth speed, firstly, the sixth driven
gear D6 and the second output shaft 140 are synchronously engaged
by operating the fourth synchronizing device S4 to the right in
FIG. 1 while the first clutch C1 operates and the second clutch C2
is released. Then, the shifting to the sixth speed may be
terminated by releasing the first clutch C1 and operating the
second clutch C2.
[0069] For shifting to the reverse speed, firstly, the reverse
driven gear R and the second output shaft 140 are synchronously
engaged by operating the third synchronizing device S3 to the right
in FIG. 1 while the first clutch C1 is released and the second
clutch C2 operates. Then, the shifting to the reverse speed may be
terminated by releasing the second clutch C2 and operating the
first clutch C1, the reverse speed having a large reduction ratio
of as much as that of the first speed.
[0070] FIG. 3 is a schematic diagram of a double clutch
transmission according to a second embodiment of the present
invention. As shown in FIG. 3, a double clutch transmission
according to a first embodiment of the present invention includes a
main input shaft 105; first and second input shafts 110 and 120;
first and second clutches C1 and C2; first, second, third, fourth,
and sixth drive gears G1, G2, G3, G4, and G6; first and second
output devices OUT1 and OUT2; and a differential gear DIFF.
[0071] Details of the main input shaft 105, first and second input
shafts 110 and 120, first and second clutches C1 and C2, and a
cooperative relationship thereamong of a double clutch transmission
according to a second embodiment are the same as has been described
in connection with the first embodiment.
[0072] The first and third drive gears G1 and G3 according to the
second embodiment are formed on the first input shaft 110, and the
second, fourth, and sixth drive gears G2, G4, and G6 are formed on
the second input shaft 120.
[0073] In further detail, the first and third drive gears G1 and G3
are disposed on the first input shaft 110 such that an end of the
second input shaft 120 is closer to first drive gear G1 than to the
third drive gear G3. In addition, the second, fourth, and sixth
drive gears G2, G4, and G6 are disposed on the second input shaft
120 such that the engine 102 is closest to the fourth drive gear
G4, further from the second drive gear G2, and farthest from the
sixth drive gear G6. In other words, regarding disposition of such
drive gears, referring to FIG. 3 related to a second embodiment of
the present invention, the first, second, third, fourth, and sixth
drive gears G1, G2, G3, G4, and G6 are disposed in a sequence of
the third drive gear G3, the first drive gear G1, the sixth drive
gear G6, the second drive gear G2, and the fourth drive gear
G4.
[0074] As shown in FIG. 3, a double clutch transmission according
to a second embodiment of the present invention further includes a
first output device OUT1 and a second output device OUT2. The first
output device OUT1 selectively changes torques of the first,
second, third, and fourth drive gears G1, G2, G3, and G4, and
outputs the changed torques. The second output device OUT2
selectively changes torques of the first, third, and sixth drive
gears G1, G3, and G6, and outputs the changed torques.
[0075] As shown in FIG. 3, the first output device OUT1 includes a
first output shaft 130; first, second, third, and fourth driven
gears D1, D2, D3, and D4; first and second synchronizing devices S1
and S2; and a first output gear 135.
[0076] The first output shaft 130 is disposed parallel to and apart
from the main input shaft 105 by a predetermined distance. The
first, second, third, and fourth driven gears D1, D2, D3, and D4
are disposed on the first output shaft 130, and they are
respectively engaged with the first, second, third, and fourth
drive gears G1, G2, G3, and G4. The first synchronizing device S1
selectively transmits torques of the first and third driven gears
D1 and D3 to the first output shaft 130. The second synchronizing
device S2 selectively transmits torques of the second and fourth
driven gears D2 and D4 to the first output shaft 130.
[0077] In addition, the first output gear 135 is disposed on the
first output shaft 130 and engaged with the differential gear DIFF
such that selectively changed torques of the first, second, third,
and fourth drive gears G1, G2, G3, and G4 may be output
therethrough to the differential gear DIFF. As shown in FIG. 3, the
second output device OUT2 includes a second output shaft 140, fifth
and sixth driven gears D5 and D6, first and second mediating gears
M1 and M2, a reverse driven gear R, third and fourth synchronizing
devices S3 and S4, and a second output gear 145.
[0078] The second output shaft 140 is disposed parallel to and
apart from the main input shaft 105 by a predetermined distance.
The fifth and sixth driven gears D5 and D6 are disposed on the
second output shaft 140, and are respectively engaged with the
third and sixth drive gears G3 and G6. The first mediating gear M1
is engaged with the first drive gear G1, and the second mediating
gear M2 is connected to the first mediating gear M1 by an idle
shaft 150.
[0079] The reverse driven gear R is engaged with the second
mediating gear M2 and is disposed on the second output shaft 140
between the sixth driven gear D6 and the second output gear 145.
Gear teeth (more specifically, the outer surface of some gear
teeth) TF of the reverse driven gear R lie close to an exterior
circumference of the second input shaft 120 between the second and
fourth drive gears G2 and G4.
[0080] The third synchronizing device S3 selectively transmits a
torque of the fifth driven gear D5 to the second output shaft 140.
The fourth synchronizing device S4 selectively transmits torques of
the sixth driven gear D6 and the reverse driven gear R to the
second output shaft 140. In addition, the second output gear 145 is
disposed on the second output shaft 140 and is engaged with the
differential gear DIFF such that selectively changed torques of the
first, third, and sixth drive gears G1, G3, and G6 may be output
therethrough to the differential gear DIFF.
[0081] In addition, the parking gear PG is disposed on the second
output shaft 140 of the first output device OUT1 between the
reverse driven gear R and the second output gear 145. In this case
the parking gear PG is disposed at an axial position corresponding
to the fourth drive gear G4 of the second input shaft. Therefore,
limited space in a transmission case may be efficiently
utilized.
[0082] In addition, when the parking gear PG is disposed on the
first output shaft 140, torque acting on the parking gear PG due to
a weight of a vehicle e.g., on a slope is reduced by a reduction
ratio between the differential gear DIFF and the second output gear
145. This implies that a torque capacity of a parking apparatus may
be minimally designed.
[0083] In addition, the parking gear PG may be positioned on the
second output shaft 140 close to an inhibitor switch and/or the
manual valve of the transmission case. Therefore, the linkage
structure for transferring a movement of a shift lever (frequently
called a transmission gear shift lever, and abbreviated as T.G.S
lever) to the manual valve of a valve body may be simplified.
[0084] Details of the first, second, third, and fourth
synchronizing devices S1, S2, S3, and S4 are the same as has been
described in connection with the first embodiment. Although minor
differences lie in connections of the synchronizing devices to
driven gears, they are obvious changes according to different
dispositions of driven gears, and need not be described in further
detail.
[0085] FIG. 3 does not illustrate a connection between the first
mediating gear M1 and the first drive gear G1, or a connection
between the second output shaft 140 and the differential gear DIFF.
This is because the first and second input shafts 110 and 120, the
first and second output shafts 130 and 140, the idle shaft 150, and
the differential gear DIFF are planarly drawn for illustrational
convenience, although they are spatially disposed.
[0086] Such a spatial disposition of the first and second input
shafts 110 and 120, the first and second output shafts 130 and 140,
the idle shaft 150, the differential gear DIFF, and the parking
gear PG appears in FIG. 4.
[0087] FIG. 4 is a drawing for illustrating a spatial relationship
of an idle shaft 150 for a reverse speed, a differential gear DIFF,
a parking gear PG, first and second input shafts 110 and 120, and
first and second output shafts 130 and 140 of a double clutch
transmission according to a second embodiment of the present
invention. FIG. 4 is a view of FIG. 3 seen from the right thereof,
and some gears shown in FIG. 1 are intentionally not shown in FIG.
4 for better understanding of the spatial relationship among
rotation axes of rotating elements.
[0088] As shown in FIG. 4, the first and second output shafts 130
and 140 are disposed apart from the second input shaft 120. The
idle shaft 150 for a reverse speed is disposed at a position in
which it may form a triangle together with the first input shaft
110 and the second output shaft 140. The first mediating gear M1 on
the idle shaft 150 is engaged with the first drive gear G1 of the
first input shaft 110, and the second mediating gear M2 on the idle
shaft 150 is engaged with the reverse driven gear R of the second
output shaft 140.
[0089] The differential gear DIFF is disposed at a position in
which it may form a triangle together with the first and second
output shafts 130 and 140, so that the differential gear DIFF is
commonly engaged with the first and second output gears 135 and 145
of the first and second output shafts 130 and 140. The parking gear
PG on the first output shaft is not engaged with any gear.
[0090] According to such structural features of a double clutch
transmission, disposition of only five drive gears on input shafts
may enable a total of seven speeds, i.e., six forward speeds and
one reverse speed. Therefore, a length of a forward six-speed
double clutch transmission may be greatly shortened.
[0091] In addition, the shortened length of the idle shaft 150 for
a reverse speed contributes to a reduction of rotational inertia of
the transmission in forward speeds, an enhancement of torque
transmission efficiency in the reverse speed, and an increase in
durability of the idle shaft 150 for a reverse speed.
[0092] In addition, the parking gear PG is disposed on the second
output shaft 140, at an axial position corresponding to the fourth
drive gear G4 of the second input shaft 120 engaged with the fourth
driven gear D4 of the first output shaft 140. Therefore, torque
acting on the parking gear PG due to a weight of a vehicle is
reduced by a reduction ratio between the differential gear DIFF and
the second output gear 145.
[0093] In addition, the parking gear PG may be positioned on the
second output shaft 140 closest to an inhibitor switch and/or the
manual valve of the transmission case. Therefore, a linkage
structure for transferring a movement of a shift lever (frequently
called a transmission gear shift lever, and abbreviated as T.G.S
lever) to the manual valve of a valve body may be simplified.
[0094] Referring back to FIG. 3, shifting operations of such a
double clutch transmission according to a second embodiment of the
present invention are hereinafter described in detail. For shifting
to the first speed, the first driven gear D1 and the first output
shaft 130 are synchronously engaged by operating the first
synchronizing device S1 to the right in FIG. 3. Then, the shifting
to the first speed may be terminated by operating the first clutch
C1.
[0095] For shifting to the second speed, firstly, the second driven
gear D2 and the first output shaft 130 are synchronously engaged by
operating the second synchronizing device S2 to the left in FIG. 3
while the first clutch C1 operates and the second clutch C2 is
released. Then, the shifting to the second speed may be terminated
by releasing the first clutch C1 and operating the second clutch
C2.
[0096] For shifting to the third speed, firstly, the third driven
gear D3 and the first output shaft 130 are synchronously engaged by
operating the first synchronizing device S1 to the left in FIG. 3
while the first clutch C1 is released and the second clutch C2
operates. Then, the shifting to the third speed may be terminated
by releasing the second clutch C2 and operating the first clutch
C1.
[0097] For shifting to the fourth speed, firstly, the fourth driven
gear D4 and the second output shaft 140 are synchronously engaged
by operating the second synchronizing device S4 to the right in
FIG. 3 while the first clutch C1 operates and the second clutch C2
is released. Then, the shifting to the fourth speed may be
terminated by releasing the first clutch C1 and operating the
second clutch C2.
[0098] For shifting to the fifth speed, firstly, the fifth driven
gear D5 and the second output shaft 140 are synchronously engaged
by operating the third synchronizing device S3 to the left in FIG.
3 while the first clutch C1 is released and the second clutch C2
operates. Then, the shifting to the fifth speed may be terminated
by releasing the second clutch C2 and operating the first clutch
C1.
[0099] For shifting to the sixth speed, firstly, the sixth driven
gear D6 and the second output shaft 140 are synchronously engaged
by operating the fourth synchronizing device S4 to the left in FIG.
3 while the first clutch C1 operates and the second clutch C2 is
released. Then, the shifting to the sixth speed may be terminated
by releasing the first clutch C1 and operating the second clutch
C2.
[0100] For shifting to the reverse speed, firstly, the reverse
driven gear R and the second output shaft 140 are synchronously
engaged by operating the fourth synchronizing device S4 to the
right in FIG. 3 while the first clutch C1 is released and the
second clutch C2 operates. Then, the shifting to the reverse speed
may be terminated by releasing the second clutch C2 and operating
the first clutch C. The reverse speed having a large reduction
ratio of as much as that of the first speed.
[0101] As can be seen from the above shifting process, a clutch
required to be operated for realization of adjacent speeds
alternately changes. In addition, adjacent speeds require different
synchronizing devices to be operated. Therefore, a release of a
current speed and a realization of a target speed may be
independently controlled during shifting from and to adjacent
speeds. In addition, during shifting to an adjacent speed, various
manipulation techniques that a driver may perform on a manual
transmission, e.g., a half-clutch operation, may be realized by
controlling engagement timing of an on-coming clutch and release
timing of an off-going clutch.
[0102] According to an embodiment of the present invention,
disposition of only four or five drive gears on input shafts may
enable a total of seven speeds, i.e., six forward speeds and one
reverse speed. Therefore, a length of a forward six-speed double
clutch transmission may be greatly shortened.
[0103] In addition, a length of the idle shaft 150 for a reverse
speed may be greatly shortened. Accordingly, a transmission may
have a light weight. It also contributes to a reduction of
rotational inertia of the idle shaft 150, and an enhancement of
torque transmission efficiency.
[0104] In addition, the parking gear PG is disposed on one output
shaft of the two output shafts, at an axial position corresponding
to one drive gear of the one input shaft engaged with one driven
gear of the other output shaft. Therefore, the limited space in a
transmission case may be efficiently utilized.
[0105] In addition, when the parking gear PG is disposed on, e.g.,
the first output shaft 130, torque acting on the parking gear PG
due to a weight of a vehicle e.g., on a slope, is reduced by a
reduction ratio between the differential gear DIFF and the first
output gear 135. This implies that a torque capacity of a parking
apparatus may be minimally designed.
[0106] In addition, the parking gear PG may be positioned on the
first output shaft 130 close to an inhibitor switch and/or the
manual valve of the transmission case. Therefore, a linkage
structure for transferring a movement of a shift lever (frequently
called a transmission gear shift lever, and abbreviated as T.G.S
lever) to the manual valve of a valve body may be simplified.
[0107] While this invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not
limited to the disclosed embodiments, but, on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *